/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * -------------------
 * CrosshairState.java
 * -------------------
 * (C) Copyright 2002-2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 24-Jan-2002 : Version 1 (DG);
 * 05-Mar-2002 : Added Javadoc comments (DG);
 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
 * 19-Sep-2003 : Modified crosshair distance calculation (DG);
 * 04-Dec-2003 : Crosshair anchor point now stored outside chart since it is
 *               dependent on the display target (DG);
 * 25-Feb-2004 : Replaced CrosshairInfo --> CrosshairState (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 13-Oct-2006 : Fixed initialisation of CrosshairState - see bug report
 *               1565168 (DG);
 * 06-Feb-2007 : Added new fields and methods to fix bug 1086307 (DG);
 * 26-Jun-2008 : Now tracks dataset index (DG);
 *
 */

package net.droidsolutions.droidcharts.core.plot;

import net.droidsolutions.droidcharts.awt.Point2D;

/**
 * Maintains state information about crosshairs on a plot between successive
 * calls to the renderer's draw method. This class is used internally by
 * JFreeChart - it is not intended for external use.
 */
public class CrosshairState {

	/**
	 * A flag that controls whether the distance is calculated in data space or
	 * Java2D space.
	 */
	private boolean calculateDistanceInDataSpace = false;

	/** The x-value (in data space) for the anchor point. */
	private double anchorX;

	/** The y-value (in data space) for the anchor point. */
	private double anchorY;

	/** The anchor point in Java2D space - if null, don't update crosshair. */
	private Point2D anchor;

	/** The x-value for the current crosshair point. */
	private double crosshairX;

	/** The y-value for the current crosshair point. */
	private double crosshairY;

	/**
	 * The dataset index that the crosshair point relates to (this determines
	 * the axes that the crosshairs will be plotted against).
	 * 
	 * @since 1.0.11
	 */
	private int datasetIndex;

	/**
	 * The index of the domain axis that the crosshair x-value is measured
	 * against.
	 * 
	 * @since 1.0.4
	 */
	private int domainAxisIndex;

	/**
	 * The index of the range axis that the crosshair y-value is measured
	 * against.
	 * 
	 * @since 1.0.4
	 */
	private int rangeAxisIndex;

	/**
	 * The smallest distance (so far) between the anchor point and a data point.
	 */
	private double distance;

	/**
	 * Creates a new <code>CrosshairState</code> instance that calculates
	 * distance in Java2D space.
	 */
	public CrosshairState() {
		this(false);
	}

	/**
	 * Creates a new <code>CrosshairState</code> instance.
	 * 
	 * @param calculateDistanceInDataSpace
	 *            a flag that controls whether the distance is calculated in
	 *            data space or Java2D space.
	 */
	public CrosshairState(boolean calculateDistanceInDataSpace) {
		this.calculateDistanceInDataSpace = calculateDistanceInDataSpace;
	}

	/**
	 * Returns the distance between the anchor point and the current crosshair
	 * point.
	 * 
	 * @return The distance.
	 * 
	 * @see #setCrosshairDistance(double)
	 * @since 1.0.3
	 */
	public double getCrosshairDistance() {
		return this.distance;
	}

	/**
	 * Sets the distance between the anchor point and the current crosshair
	 * point. As each data point is processed, its distance to the anchor point
	 * is compared with this value and, if it is closer, the data point becomes
	 * the new crosshair point.
	 * 
	 * @param distance
	 *            the distance.
	 * 
	 * @see #getCrosshairDistance()
	 */
	public void setCrosshairDistance(double distance) {
		this.distance = distance;
	}

	/**
	 * Evaluates a data point and if it is the closest to the anchor point it
	 * becomes the new crosshair point.
	 * <P>
	 * To understand this method, you need to know the context in which it will
	 * be called. An instance of this class is passed to an
	 * {@link org.jfree.chart.renderer.xy.XYItemRenderer} as each data point is
	 * plotted. As the point is plotted, it is passed to this method to see if
	 * it should be the new crosshair point.
	 * 
	 * @param x
	 *            x coordinate (measured against the domain axis).
	 * @param y
	 *            y coordinate (measured against the range axis).
	 * @param transX
	 *            x translated into Java2D space.
	 * @param transY
	 *            y translated into Java2D space.
	 * @param orientation
	 *            the plot orientation.
	 * 
	 * @deprecated Use
	 *             {@link #updateCrosshairPoint(double, double, int, int, double, double, PlotOrientation)}
	 *             . See bug report 1086307.
	 */
	public void updateCrosshairPoint(double x, double y, double transX,
			double transY, PlotOrientation orientation) {
		updateCrosshairPoint(x, y, 0, 0, transX, transY, orientation);
	}

	/**
	 * Evaluates a data point and if it is the closest to the anchor point it
	 * becomes the new crosshair point.
	 * <P>
	 * To understand this method, you need to know the context in which it will
	 * be called. An instance of this class is passed to an
	 * {@link org.jfree.chart.renderer.xy.XYItemRenderer} as each data point is
	 * plotted. As the point is plotted, it is passed to this method to see if
	 * it should be the new crosshair point.
	 * 
	 * @param x
	 *            x coordinate (measured against the domain axis).
	 * @param y
	 *            y coordinate (measured against the range axis).
	 * @param domainAxisIndex
	 *            the index of the domain axis for this point.
	 * @param rangeAxisIndex
	 *            the index of the range axis for this point.
	 * @param transX
	 *            x translated into Java2D space.
	 * @param transY
	 *            y translated into Java2D space.
	 * @param orientation
	 *            the plot orientation.
	 * 
	 * @since 1.0.4
	 */
	public void updateCrosshairPoint(double x, double y, int domainAxisIndex,
			int rangeAxisIndex, double transX, double transY,
			PlotOrientation orientation) {

		if (this.anchor != null) {
			double d = 0.0;
			if (this.calculateDistanceInDataSpace) {
				d = (x - this.anchorX) * (x - this.anchorX)
						+ (y - this.anchorY) * (y - this.anchorY);
			} else {
				double xx = this.anchor.getX();
				double yy = this.anchor.getY();
				if (orientation == PlotOrientation.HORIZONTAL) {
					double temp = yy;
					yy = xx;
					xx = temp;
				}
				d = (transX - xx) * (transX - xx) + (transY - yy)
						* (transY - yy);
			}

			if (d < this.distance) {
				this.crosshairX = x;
				this.crosshairY = y;
				this.domainAxisIndex = domainAxisIndex;
				this.rangeAxisIndex = rangeAxisIndex;
				this.distance = d;
			}
		}

	}

	/**
	 * Evaluates an x-value and if it is the closest to the anchor x-value it
	 * becomes the new crosshair value.
	 * <P>
	 * Used in cases where only the x-axis is numerical.
	 * 
	 * @param candidateX
	 *            x position of the candidate for the new crosshair point.
	 * 
	 * @deprecated Use {@link #updateCrosshairX(double, int)}. See bug report
	 *             1086307.
	 */
	public void updateCrosshairX(double candidateX) {
		updateCrosshairX(candidateX, 0);
	}

	/**
	 * Evaluates an x-value and if it is the closest to the anchor x-value it
	 * becomes the new crosshair value.
	 * <P>
	 * Used in cases where only the x-axis is numerical.
	 * 
	 * @param candidateX
	 *            x position of the candidate for the new crosshair point.
	 * @param domainAxisIndex
	 *            the index of the domain axis for this x-value.
	 * 
	 * @since 1.0.4
	 */
	public void updateCrosshairX(double candidateX, int domainAxisIndex) {

		double d = Math.abs(candidateX - this.anchorX);
		if (d < this.distance) {
			this.crosshairX = candidateX;
			this.domainAxisIndex = domainAxisIndex;
			this.distance = d;
		}

	}

	/**
	 * Evaluates a y-value and if it is the closest to the anchor y-value it
	 * becomes the new crosshair value.
	 * <P>
	 * Used in cases where only the y-axis is numerical.
	 * 
	 * @param candidateY
	 *            y position of the candidate for the new crosshair point.
	 * 
	 * @deprecated Use {@link #updateCrosshairY(double, int)}. See bug report
	 *             1086307.
	 */
	public void updateCrosshairY(double candidateY) {
		updateCrosshairY(candidateY, 0);
	}

	/**
	 * Evaluates a y-value and if it is the closest to the anchor y-value it
	 * becomes the new crosshair value.
	 * <P>
	 * Used in cases where only the y-axis is numerical.
	 * 
	 * @param candidateY
	 *            y position of the candidate for the new crosshair point.
	 * @param rangeAxisIndex
	 *            the index of the range axis for this y-value.
	 * 
	 * @since 1.0.4
	 */
	public void updateCrosshairY(double candidateY, int rangeAxisIndex) {
		double d = Math.abs(candidateY - this.anchorY);
		if (d < this.distance) {
			this.crosshairY = candidateY;
			this.rangeAxisIndex = rangeAxisIndex;
			this.distance = d;
		}

	}

	/**
	 * Returns the anchor point.
	 * 
	 * @return The anchor point.
	 * 
	 * @see #setAnchor(Point2D)
	 * 
	 * @since 1.0.3
	 */
	public Point2D getAnchor() {
		return this.anchor;
	}

	/**
	 * Sets the anchor point. This is usually the mouse click point in a chart
	 * panel, and the crosshair point will often be the data item that is
	 * closest to the anchor point. <br>
	 * <br>
	 * Note that the x and y coordinates (in data space) are not updated by this
	 * method - the caller is responsible for ensuring that this happens in
	 * sync.
	 * 
	 * @param anchor
	 *            the anchor point (<code>null</code> permitted).
	 * 
	 * @see #getAnchor()
	 */
	public void setAnchor(Point2D anchor) {
		this.anchor = anchor;
	}

	/**
	 * Returns the x-coordinate (in data space) for the anchor point.
	 * 
	 * @return The x-coordinate of the anchor point.
	 * 
	 * @since 1.0.3
	 */
	public double getAnchorX() {
		return this.anchorX;
	}

	/**
	 * Sets the x-coordinate (in data space) for the anchor point. Note that
	 * this does NOT update the anchor itself - the caller is responsible for
	 * ensuring this is done in sync.
	 * 
	 * @param x
	 *            the x-coordinate.
	 * 
	 * @since 1.0.3
	 */
	public void setAnchorX(double x) {
		this.anchorX = x;
	}

	/**
	 * Returns the y-coordinate (in data space) for the anchor point.
	 * 
	 * @return The y-coordinate of teh anchor point.
	 * 
	 * @since 1.0.3
	 */
	public double getAnchorY() {
		return this.anchorY;
	}

	/**
	 * Sets the y-coordinate (in data space) for the anchor point. Note that
	 * this does NOT update the anchor itself - the caller is responsible for
	 * ensuring this is done in sync.
	 * 
	 * @param y
	 *            the y-coordinate.
	 * 
	 * @since 1.0.3
	 */
	public void setAnchorY(double y) {
		this.anchorY = y;
	}

	/**
	 * Get the x-value for the crosshair point.
	 * 
	 * @return The x position of the crosshair point.
	 * 
	 * @see #setCrosshairX(double)
	 */
	public double getCrosshairX() {
		return this.crosshairX;
	}

	/**
	 * Sets the x coordinate for the crosshair. This is the coordinate in data
	 * space measured against the domain axis.
	 * 
	 * @param x
	 *            the coordinate.
	 * 
	 * @see #getCrosshairX()
	 * @see #setCrosshairY(double)
	 * @see #updateCrosshairPoint(double, double, double, double,
	 *      PlotOrientation)
	 */
	public void setCrosshairX(double x) {
		this.crosshairX = x;
	}

	/**
	 * Get the y-value for the crosshair point. This is the coordinate in data
	 * space measured against the range axis.
	 * 
	 * @return The y position of the crosshair point.
	 * 
	 * @see #setCrosshairY(double)
	 */
	public double getCrosshairY() {
		return this.crosshairY;
	}

	/**
	 * Sets the y coordinate for the crosshair.
	 * 
	 * @param y
	 *            the y coordinate.
	 * 
	 * @see #getCrosshairY()
	 * @see #setCrosshairX(double)
	 * @see #updateCrosshairPoint(double, double, double, double,
	 *      PlotOrientation)
	 */
	public void setCrosshairY(double y) {
		this.crosshairY = y;
	}

	/**
	 * Returns the dataset index that the crosshair values relate to. The
	 * dataset is mapped to specific axes, and this is how the crosshairs are
	 * mapped also.
	 * 
	 * @return The dataset index.
	 * 
	 * @see #setDatasetIndex(int)
	 * 
	 * @since 1.0.11
	 */
	public int getDatasetIndex() {
		return this.datasetIndex;
	}

	/**
	 * Sets the dataset index that the current crosshair values relate to.
	 * 
	 * @param index
	 *            the dataset index.
	 * 
	 * @see #getDatasetIndex()
	 * 
	 * @since 1.0.11
	 */
	public void setDatasetIndex(int index) {
		this.datasetIndex = index;
	}

	/**
	 * Returns the domain axis index for the crosshair x-value.
	 * 
	 * @return The domain axis index.
	 * 
	 * @since 1.0.4
	 * 
	 * @deprecated As of version 1.0.11, the domain axis should be determined
	 *             using the dataset index.
	 */
	public int getDomainAxisIndex() {
		return this.domainAxisIndex;
	}

	/**
	 * Returns the range axis index for the crosshair y-value.
	 * 
	 * @return The range axis index.
	 * 
	 * @since 1.0.4
	 * 
	 * @deprecated As of version 1.0.11, the domain axis should be determined
	 *             using the dataset index.
	 */
	public int getRangeAxisIndex() {
		return this.rangeAxisIndex;
	}

}
